"I think the inclusion of "nationalism and often racism" is an editorial lapse here. Mussolini wasn't racist the way the Nazis were"

It is not, Mussolini was member of the Italian communist party but decided he wanted to create their own party, also socialist but nationalist.

This way it was totally independent from the socialist International(soviet Russia controlled) because he did not wanted to become a satellite state.

Racism was applied as Mussolini wanted to recover the glory days of the Roman Empire, the Italians as a superior race that "dominates the world".